Endotracheal tubes are used in a variety of medical procedures to provide an unobstructed air passage to a patient's trachea. In many emergency situations, it is necessary to intubate a patient as quickly as possible in order to provide a secure airway to the patient's lungs or to permit forced ventilation thereof while preventing introduction of gastric contents. Failure to quickly supply oxygen to the lungs can result in brain damage or death of the patient.
Intubation is often difficult because of an abnormal anatomy encountered in the patient's airway. One of the steps in an intubation procedure is maneuvering the tube into the patient's trachea rather than the patient's esophagus. As endotracheal tubes are generally formed of a soft, pliable material, a stylet or other manipulation device is often used to assist directing the endotracheal tube during intubation.
The user inserts the stylet into the tube and folds one end of the stylet around the outer end of the endotracheal tube. The user then bends the tube and stylet to approximately what the he estimates the contour of the patient's throat is likely to be (usually J-shape). With the help of a laryngoscope, the user inserts the stylet and endotracheal tube into the patient's mouth and throat until it reaches the patient's trachea. It is often difficult for a user to obtain the proper shape with a flexible stylet and to successfully insert the endotracheal tube into the patient's trachea.
If the user fails to intubate the patient on the first attempt, he must remove the tube and stylet from the patient, grasp the tube and stylet, re-bend it accordingly, re-ventilate the patient, and again insert the tube and stylet into the patient.
Mechanical guides have been developed to assist intubation of endotracheal tubes. For example, U.S. Pat. No. 5,259,377 discloses a stylet comprising a flexible member, a collar slidably mounted thereon, a handle mounted at one end of and along the longitudinal axis of the flexible member and a fixed length filament attached to a distal end of the flexible member and the collar. A portion of the stylet is telescopically received within an endotracheal tube. The user may selectively deflect or induce curvature to the endotracheal tube by applying force to the handle along the axis of the flexible member and inducing movement of the handle with respect to the collar when the filament is under tension. Alternatively, the user may selectively deflect the endotracheal tube by inducing movement of the collar with respect to the handle when the filament is under tension.